This invention relates to an adhesive, sealing and coating compound based on a copolymer of styrene with at least one other comonomer and a polyalkylene oxide as plasticizer.
Compounds of the type in question are known. Thus, U.S. Pat. No. 4,869,934 describes a composition for smoothing, cleaning and coating floors which consists, for example, of the following components: 31.2 parts by weight of a copolymer of butyl methacrylate, methacrylic acid, methyl methacrylate and styrene in a ratio of 10:18:52:20, 1.6 parts by weight of the permanent plasticizer (BuOCH2CH2O)3PO and 7.0 parts by weight of the volatile plasticizer Me(OC3H6)2OH and about 48 parts by weight of water. This known composition has the disadvantage that at least the volatile plasticizers pollute the environment or are even toxic.
The product xe2x80x9cPlastilit 3060xe2x80x9d is described in BASF""s Technical Information Pamphlet TI/ED 1115 d-1 of January, 1984. This product is a polypropylene glycol alkyl phenyl ether which is used as a plasticizer for polymer dispersions, more particularly for polyacrylates. Polymers specifically mentioned include a copolymer of styrene and butyl acrylate and a copolymer of ethyl acrylate, ethyl hexyl acrylate and acrylonitrile. Compositions of the type in question may be used, for example, as sealing compounds which form a skin shortly after application, undergo relatively little post-curing and exhibit better elastic behavior at low temperatures. In addition, in conjunction with fillers, they form paste-like tile adhesives which combine favorable tensile strengths with high elasticity. The plasticizer has an elasticizing effect on the copolymer without significantly affecting the water absorption of the film. Thus, the elongation of a film increases almost linearly from about 300% to 4,000% after the addition of 9% of plasticizer. So far as the biological effect of the plasticizer is concerned, the information available suggests that it has no health-damaging effects although there could be some irritation of the skin and mucous membrane after prolonged exposure. Another disadvantage is that the viscosity of the dispersion is significantly increased by the addition of Plastilit 3060. The addition of fillers is seriously limited as a result. In addition, there is hardly any scope for adding other plasticizers.
The same disadvantages also apply to the following two documents. Polish patent PL 119091 describes a non-toxic and non-inflammable adhesive for ceramics and plastics which, in addition to an acrylate/styrene dispersion, contains polypropylene glycol alkyl phenyl ether, fillers, organic solvents and water.
German patent DE 36 38 224 describes an elastic sealing material which contains a styrene/butadiene rubber, an xcex1-methyl styrene polymer, solvents, such as hydrocarbons and aromatic hydrocarbons, and polypropylene glycol alkyl phenyl ether.
Czech patent CS 259825 describes a contact adhesive for labels and tapes which mainly contains a copolymer of acrylates, unsaturated carboxylic acids and, optionally, styrene, alkyl styrene or vinyl acetate. Other components are organic solvents and plasticizers such as, for example, polyethylene glycol and polypropylene glycol.